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Intergumentary System, Effect of aging, subcutaneous layer, plexus, uv can…
Intergumentary System
general functions
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Excretion of sweats (water, mineral salts and organic wastes )
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As first barrier in immune system (densely packed tissues prevent most of the pathogens from entering body)
Detection of touch, pain, pressure and temperature stimuli
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Pigmentation
type of pigments
Melanin
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The skin color depends on size and quantity of melanosomes (pale-skinned: melanosomes destroyed, dark-skinned: melanosomes present are larger and more)
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Melanin is synthesis from thyrosine (amino acid), and packaged in vesicles (melanosomes) travel to nearby keratinocytes
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carotene
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Can be converted into vitamin A which is essential in epithelial maintenance and synthesis of photoreceptor pigments in the eyes
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Two major parts
Cutaneous
Epidermis
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Consist of stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum and stratum basale.
Stratum granulosum
Keratinocytes produce keratin. As cell grows, the cell flattened and become thinner while keratin become thicker
As a result, the plasma membrane gradually thicken (keratin) and cell die due to lack of nutrients and dehydration (pushed far from the blood vessels providing the oxygen and nutrients)
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Stratum basale
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Contains basal/stem cells, melanocytes and tactile cells
Stratum corneum
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Consist of layers of flattened, dead, interlocking keratinocytes
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Effect of aging
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Decreased blood supply to dermis, thus decreasing the ability of temperature regulating
subcutaneous layer
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Contains primarily adipose tissue. 80% of body fats is stored beneath the skin (the fat distribution will change along the growing process)
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The rest of layers contains capillaries and no vital organs, thus make it useful for drugs administration (injection)
plexus
Cutaneous plexus
supply nutrients and oxygen to adipose tissues, branches supply the hair folicles, sweats gland and others
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uv can cause the skin to burn, DNA mutation on skin, age premature, and lost of skin elascity
When injury occured, the site of injury will bleed. At this rate the hemostasis will occur, to stop the bleeding, the blood clotting occurs and the blood vessels contract to minimize bleeding. The leucocytes will accumulate at the site of injury to kill the bacteria to prevent infection. Mast cells trigger an inflammatory response. At this period the site of injury will remain painful for a certain period, based on situation.
After several hours, a scab formed and cell of stratum basale (basal cells, melanocytes and tactile cells) migrate along the edges of wound. Phagocytic cells (neutrophil and monocytes) are removing debris, and more of these cells will arrived with enhanced circulation in the area.
After a week, the scab has been undermined by epidermal cells migrating over the collagen fiber meshwork produced by fibroblast proliferation and activity. Phagocytic activity around the site almost ended and the fibrin clot is dissolving.
After several weeks, the scab shed and
new epidermis is formed on surface of injury site. A shallow depression marks the injury site, fibroblast in dermis continue to create scar tissues that will gradually elevate the overlying epidermis